Abstract： Objective:To investigate the effects of hyperbaric oxygen therapy (HBOT) on elderly patients with primary nephrotic syndrome (PNS) and its influence on fibrinogen (FIB) and insulin-like growth factor 1 (IGF-1).Methods:A total of 90 elderly patients with PNS admitted to Jiangjin Central Hospital from February 2017 to February 2019 were enrolled and evenly divided into control group and HBOT group according to the random number table method. The control group received conventional treatment of glucocorticoid combined with cyclophosphamide, and the HBOT group was additionally treated with HBOT. The levels of serum lipids, inflammatory factors, FIB, and IGF-1 were measured before and after the treatment. And the clinical efficacies and the incidence of PNS complications of the two groups were compared after the treatment.Results:The clinical efficacy of HBOT group was significantly better than that of the control group ( P<0.05). Before treatment, there was no significant difference in biochemical testing results between the two groups ( P>0.05). After the treatment, cholesterol (CHOL), triglyceride (TG), hypersensitive C-reactive protein (hs-CRP), interleukin (IL-6), and FIB of both groups were significantly decreased, and these results in HBOT group were all lower than those in the control group ( P<0.05). After treatment, the levels of IGF-1 of both groups were increased, and the level of IGF-1 of the HBOT group was higher than that of the control group ( P<0.05). There were no HBOT-related adverse reactions in the HBOT group; and the incidence of PNS complications such as embolism, gastrointestinal bleeding, and vomiting in the HBOT group was significantly lower than that in the control group ( P<0.05). Conclusion:HBOT can significantly improve the therapeutic effect on elderly PNS patients, reduce the incidence of complications, and improve the prognosis, which may be attributed to the effect of HBOT in inhibiting inflammatory reaction and improving coagulation function and bone metabolism.